Conventionally, there have been provided direct current (DC) power sockets which can intercommunicate between terminal devices and power line carrier communication networks supporting telecommunications standards with a power delivery (Refer to Patent Literature 1, for example).
There are Power over Ethernet (PoE) technology and Universal Serial Bus (USB) technology as a power delivery technology using data lines (Refer to Non Patent Literature 1, for example).
As the USB technologies, there are USB 2.0 Standard up to maximum supply power of 2.5 W, USB 3.0 Standard up to maximum supply power of 4.5 W, and Battery Charging Standard (BCS) Revision 1.2 up to maximum supply power of 7.5 W according to the power delivery level.
A USB Power Delivery (USB PD) Specification Revision 1.0 is compatible with existing cables and connectors, and coexists also with the USB 2.0 Standard, the USB 3.0 Standard, and the USB battery charging standard (BCS) Revision 1.2. In such a standard, values of the charging current and voltage is selectable within a range of voltage 5V-12V-20V and a range of current 1.5 A-2 A-3 A-5 A, and the USB electric charging and power transmission can be achieved to be 10 W, 18 W, 36 W, 65 W, and the maximum of 100 W.
DC/DC converters have been used as a power source for achieving such a power delivery. There are a diode rectification system and a synchronous rectification method in the DC/DC converters.